The present invention relates to the field of carpet manufacture, and more particularly to methods and apparatus for carving patterns in carpet pile.
As is known, carpet typically includes a backing or base and a pile that is mounted to such base by any of a variety of known processes. As has been recognized in the past, designers and artisans have employed various design treatments with respect to carpeting used on both floors and walls. In particular, decorative designs have been carved in the carpet pile using hand-held electric or air powered carpet shears or clippers.
In the past, to carve decorative designs in carpet pile, it had been suggested to use templates, to pre-mark the carpet and manually carve a pattern in the pile and to use automated, computer controlled carving tables. Since carved effects can involve complex, intricate decorative designs, computer controlled equipment is preferred, not only for purposes of reliability and repeatability, but also to reduce the cost of having a highly skilled artisan engage in such a time consuming task.
One such computer controlled device, disclosed in U.S. Pat. No. 4,793,033xe2x80x94Schneider, et al. and incorporated herein by reference, includes a carriage mechanism adapted to move a clipping mechanism in two dimensions, i.e., to move the clipping mechanism in X and Y directions. This movement is said to be controlled by a computer having a memory into which desired patterns have been stored. In particular, the carriage mechanism includes a table on which a first pulley system moves a wheeled gantry-like structure in one direction and on which a second pulley system located on the gantry moves a wheeled platform in a second perpendicular direction. The clipping mechanism is said to be attached to the platform via a manually adjustable tripod mount which is said to permit variation of the angular orientation of the clipping mechanism. It is asserted that other disclosed mechanisms can move the clipping mechanism vertically as well as rotationally.
Unfortunately, such a computer controlled device suffers from several problems. First, because the clipping mechanism is moved via a tripod mount, setting or making changes to the angular orientation of the clipping blades will result in a relocation of the leading edge or leading prongs, i.e., the beginning carving point will be offset from the pivot point in the mount. Since the angular setting or adjustment is manually achieved, it will be necessary, if even possible, to align/calibrate or re-align/calibrate the computer program and the clipper blades after each manual adjustment to allow for the relocation of the leading edge, so that the clipping blades carve in the exact locations specified by the computer. Second, because the device is automated, the clipping blades will be moving relative to one another for extended periods of time. The friction forces generated during the clipping operation will lead to elevated temperatures of the clipping blades. It has been found that such elevated temperatures cause the clipping blades to become dull faster, requiring replacement, thereby adding to the cost of operations. Although Schneider et al. suggests providing a lubricant drip to the blades and a vacuum operation, these features are not believed sufficient to maintain acceptable blade temperature for extended periods.
In addition, the Schneider et al. device does not account for pile deflection. It has been found that when a clipping mechanism is brought into contact with the carpet pile, the bottom of the clipping mechanism tends to compress or deflect the pile directly under the clipping blades. This deflection or compression can cause unwanted imperfections, i.e., extraneous tufts. Moreover, for direction changes where a clipping blade would be moved away from and then onto the pile, the tuft imperfection itself can be deflected or compressed, making matters worse. The presence of such tuft imperfections will require a manual finishing operation in order to achieve the desired appearance, or alternatively the design must be re-run, possibly several times. Moreover, carpet pile over an extended area can have a random angle, bias or direction. During manual carving operations, the artisan will frequently brush the pile with a hand in order to orient the pile in a desired direction before clipping. The Schneider et al. device makes no mention, nor does it suggest a solution to this problem.
Although not resolving any of the above described problems, U.S. Pat. No. 5,285,558xe2x80x94Carder et al., incorporated herein by reference, discloses a hand operated device, containing a clipping mechanism, which is moved manually to trim carpet pile or to bevel the edge of the pile. In relation to the beveling operation, Carder et al. disclose a mounting bracket which permits pivoting of the clipping mechanism. Unfortunately, this pivoting movement also results in a relocation of the leading edge or leading prongs.
Consequently, a need still exists for a carpet clipping device which controls clipping blade temperature during extended clipping operation, provides accurate angled orientation of the clipping blades, accounts for pile compression/deflection whenever the clipping blade is moved against the pile and which accounts for random pile direction.
In addition to carving carpet, designers and artisans have formed decorative designs by carefully separating and recombining multiple pieces of carpet into a new composite or fabricated carpet. Typically, the multiple pieces include several colors and/or textures, and the composite or fabricated carpet therefore includes the several colors and/or textures which in combination connote the decorative design.
When forming decorative designs it may of course be desirable to both carve a piece of carpet and then separate the carved piece for recombining with one or more other pieces. Alternatively, the separating may take place before the carving. In either case, separating typically takes place along grooves or valleys created in the carpet during carving, where such carving is performed either before or after the separating. Typically, the carving is performed from the top or pile side of the carpet and the separating is performed from the backing side. However, this requires that the carpet be moved between the carving and separating operations. Especially where the carving and separating are performed in an automated manner, a serious issue arises in that the movement between the carving and separating operations introduces the opportunity for mis-alignment of the carpet as between the carving and separating operations. That is, unless the carpet is positioned very carefully after the first operation, the results of the second operation will not align with the results of the first operation. Accordingly, a need exists for an apparatus and method for both carving and separating, wherein mis-alignment is minimized if not eliminated.
As is known, carpet is woven or otherwise formed at a mill or the like. During such weaving/forming, the carpet by the nature of the weaving/forming process is imparted with a natural grain, whereby the carpet pile tends to xe2x80x98leanxe2x80x99 or deflect in the direction of the grain. When carving carpet in particular, the xe2x80x98layxe2x80x99 of the grain can affect the actual position of the carving on the carpet pile. That is, as between carving across the grain, carving against the grain, carving with the grain, and carving at angles with respect to the grain, the result of the carve will appear at slightly different positions on the carpet pile as compared with the intended position. Accordingly, a need exists for a method for carving a carpet pile whereby the direction of the grain is taken into account such that the result of the carve occurs at the appropriate position on the carpet pile.
When carving and/or separating carpet, it can occur that the carving and/or separating is interrupted by a mechanical malfunction. For example, the carver and/or separator may snag on the carpet, may lose the flow of ventilation, may lose the flow of lubrication, etc. In any instance of such mechanical malfunction, it is preferable that such malfunction be detected as soon as possible in order that such malfunction does not damage and/or ruin the carpet and/or the carving and/or separating tool. Accordingly, a need exists for an apparatus and method for detecting most if not all mechanical malfunctions in a relatively simple manner.
The aforementioned need for avoiding mis-alignment as between carving and separating operations is addressed by an automated apparatus and method for forming a decorative design in carpet in accordance with one embodiment of the present invention. In the apparatus and method, the carpet is secured to a table and a carriage is controlled and moved over the table by a computer. A carver is mounted to the carriage and is controlled by the computer to carve a design into the carpet secured on the table. In addition, a separator is mounted to the carriage and is controlled by the computer to separate the carved carpet secured on the table into a plurality of pieces.
The aforementioned need for taking grain into account during carpet carving and/or separating is addressed by a method of carving a design in carpet mounted to an automated carving table in accordance with one embodiment of the present invention. The carpet has a grain extending in a first particular direction, wherein carving in a second particular direction produces an actual result offset from an intended result by a quantified offset. In the method, the first direction and second directions are determined and a relationship therebetween is calculated. An offset associated with such relationship is then determined, and the determined offset is employed to position a carver during carving of the design in the carpet in the second direction. Thus, the employed offset produces an actual result that aligns with the intended result.
The aforementioned need for mechanical malfunction detection is addressed by a method for operating an automated carpet tool in accordance with one embodiment of the present invention. The carpet tool during operation emits vibrations at a plurality of frequencies, and during normal operation emits vibrations at a particular dominant frequency. In the method, the vibrations emitted by the carpet tool are sensed, and it is determined whether the sensed vibrations are within a normal range about the particular dominant frequency of the carpet tool. If not, operation of the carpet tool is stopped, wherein it is presumed that a mechanical malfunction has taken place. In a variation, an obstructing malfunction such as a carpet snag in connection with a carver is alleviated by use of a spring hinge mount for such carver.